Research on Analysis and Control of Annular Pressure in Ultra-deep Gas Wells
Ultra-deep gas wells are affected by complex working conditions such as high temperature,high pres-sure,and corrosive media,leading to severe challenges to wellbore integrity.Annular pressure risk is one of the important technical problems in wellbore integrity.Focusing on the problem of annular pressure in ultra-deep gas wells,this paper systematically summarizes the research progress and achievements of domestic and foreign ex-perts and scholars,including the formation mechanism,prediction method,and its influence on wellbore integrity of annular pressure.Finally,a safety control process of annular pressure is proposed from the aspects of the maxi-mum allowable value of annular pressure,annular pressure type diagnosis and well integrity monitoring,which provides a valuable reference for the safe and efficient development and design control of ultra-deep gas wells.The analysis indicates that accurately prediction of annular pressure is the basic premise for evaluating the risk of annular pressure.It is necessary to fully consider the changes in temperature,fluid properties,fluid volume,and annulus volume in the calculation.The risk assessment of annular pressure is mainly reflected in the loading ca-pacity of the casing and the sealing reliability of the cement sheath.The wellbore pressure safety management process divides three steps:calculation of the maximum allowable annular pressure,diagnosis of annular pressure types,and integrity testing of the wellbore,which can provide technical ideas to effectively prevent the potential risk of annular pressure.
ultra-deep gas wellsannular pressurewellbore integrityprediction methodrisk assessment
NETL
NSTL
万方数据
